Do you deliver your mail with maildrop? If not, this post is only for your "amusement".

My mailserver runs Postfix as MTA and maildrop as MDA, a pretty common setup I'd say. And it happens that maildrop supports quota. It supports it so good, that I have no idea how to disable that support, but I also actually never cared, as my user database declares each user has 10GB quota for mails (courier's authtest says "Quota: 10000000000S", so does the configuration). And 10GB should be enough for everybody, right?

Well, so I thought until I noticed that my Icedove indicated a 99% full mailbox and shortly afterwards maildrop stopped delivering mails with "maildir over quota". Looking at the maildirsize file in my maildir, I noticed that the quota is set to 1410065408S, a mere 1.4GB. Where does this number come from? The proficient reader will quickly see that 10000000000 mod 2^32 = 1410065408, so this is actually an integer overflow happening somewhere in the code handling the maildirsize file (read: in maildrop). A short dig through the Debian BTS revealed a bug from 2003, saying exactly the same. The bug also indicated, the issue is fixed since maildrop 2.5. A short cowbuilder run later, I had a maildrop_2.5.5-2_i386.deb, installed it and after the next mail delivery, my quota was at 10GB as it should.

TL;DR: If you run into strange "maildir over quota" errors with maildrop on Debian Squeeze, get a newer maildrop (or backport that single patch to Squeeze's maildrop).

Comments

this will remove all quota. But I would strongly suggest you to switch to something better than Maildrop. It had (and still has) many shortcomings, one of them being that you can totally destroy your system from within a .maifilter file. Things like this aren’t possible if you switch to let’s say Dovecot Sieve, which I have switched to (from maildrop).